COMMON BILE-DUCT LIGATION IN THE RAT - A MODEL OF INTRAPULMONARY VASODILATATION AND HEPATOPULMONARY SYNDROME

Hepatopulmonary syndrome (HPS) causes impaired oxygenation due to intr apulmonary vasodilatation in patients with cirrhosis. Chronic common b ile duct ligation (CBDL) in the rat results in gas-exchange abnormalit ies similar to HPS, but intrapulmonary vasodilatation has not been eva luated. We assess intrapulmonary vasodilatation, measured in vivo, aft er CBDL. Sham, 2- and 5-wk CBDL, and 3-wk partial portal vein ligated (PVL) rats had hepatic and lung injury, portal. pressure, and arterial blood gases assessed. The pulmonary microcirculation was evaluated by injecting microspheres (size range 5.5-10 mu m) intravenously and mea suring the size and number of microspheres bypassing the lungs in arte rial blood. CBDL animals developed progressive hepatic injury and port al hypertension accompanied by gas-exchange abnormalities and intrapul monary vasodilatation. PVL animals, with a similar degree of portal hy pertension, did not develop intrapulmonary vasodilatation or abnormal gas exchange. No lung injury was observed. CBDL, but not PVL, causes p rogressive intrapulmonary vasodilatation, which accompanies worsening arterial gas exchange. These findings validate CBDL as a model to stud y HPS.